The Collaborative International Dictionary
Irideous
Iridaceous \Ir`i*da"ceous\, Irideous \I*rid"e*ous\, a. [From NL. Iris, Iridis, the Iris.] (Bot.) Pertaining to, or resembling, a large natural order of endogenous plants ( Iridace[ae]), which includes the genera Iris, Ixia, Crocus, Gladiolus, and many others.
Wiktionary
irideous
a. (context botany English) Of or pertaining to the irises (of family Iridaceae).